The use of ultrasonic techniques in the evaluation of the meat yield and quality of livestock has gradually been developing over the past few years, and it is now well established that such techniques provide a feasible way to grade the qaulity of animal carcasses. U.S. Pat. No. 4,099,420 to Stouffer, assigned to the Asssignee of the present application, discloses one such technique for obtaining measurements needed for carcass measurement and inspection, but it has been found that the device disclosed therein not only is too complex, but does not provide, in an accurate, reliable, and consistent manner, the information needed for rapid evaluation and grading of carcasses.
After a meat animal such as a hog is slaughtered, it may be graded for quality by a grader who evaluates each carcass. At the present time, this grading is done by a visual inspection. Because the grade assigned to a carcass determines the price at which it can be sold, the grading has a significant economic impact. However, as is well known in the industry, this is a highly subjective evaluation of the carcass, and since small variations in grading can have an extremely large economic impact on a large producer, there is a strong economic pressure to make the process more objective, so that grading will more accurately reflect the true value of the carcass.
The ultrasonic techniques exemplified by the aforementioned U.S. Pat. No. 4,099,420 have helped to overcome the problem of subjective judging, for such devices have shown that through the use of ultrasonic transducers, it is possible to obtain an accurate reading of the fat content and muscling of not only carcasses, but live animals as well. However, the mere existence of ultrasonic techniques has not solved all of the problems that have been encountered in the grading of meat. For example, in order to get consistent and comparable results, it is necessary to measure in the same location on the carcass each time and to compensate for the fact that the multiple layers of fat in a hog carcass produce multiple readings in an ultrasonic transducer. Furthermore, since many available transducers are not able to scan a complete cross-section of an area of interest, time consuming multiple readings and interpretations have been required, and since it is necessary, on a commercial scale, to be able to grade hog carcasses at a high rate of speed, for example, 300-1000 carcasses per hour, speed and ease of operation of any ultrasonic device becomes essential. It has been found that devices such as that illustrated in U.S. Pat. No. 4,099,420 are too complex to permit the rapid use required for commercial evaluation of hog carcasses, for such devices have required the use of coupling fluids, spring-loaded transducers, multiple readings, and the like to accommodate to different shapes and sizes of carcasses as they pass by a grading station. Such complexities slow down the evaluation process and do not provide the economies that are necessary to make the conversion to ultrasonic grading techniques economically feasible at the present time. What is required, then, is a transducer device that will provide rapid, reliable information concerning a carcass, and will provide information that can be used quickly and easily for a more accurate evaluation and grading of the carcass than is possible through visual inspection. Absent an improved rate and accuracy of reading, a mechanical device for evaluation will not find acceptance in the industry.